Why Manage for Diversity?
By Rachel Mealor, UW Extension Range Specialist
The Merriam-Webster dictionary defines diversity as the condition of having or being composed of differing elements. Diversity can pertain to various things, but it is often discussed with regard to the environment, and particularly rangeland systems. Diversity exists at various scales within our rangelands as well. Plant communities can differ greatly, and so can landscapes, or even the genetic composition of plants and animals.
I have been preparing to take a trip to Mongolia, and as my departure time has approached, the topic of diversity is a concept I have been giving much thought. So, I pose the question, why would a landowner actively manage for diversity? There are various reasons a person would alter their management strategy to increase diversity, and we will discuss just a few in this article.
Diversity can help protect a system against catastrophic failure, such as the loss of productivity, stability or genetic variation. For example, if a system were strongly dominated by only one species, and that system were impacted by a pathogen, the impact of that pathogen could be devastating if the community were comprised of only one susceptible species. If there were greater diversity, the system may not be as severely impacted if there were other species that were not impacted by that pathogen.
Increasing diversity in a system can also improve the value of the community for various animal species. A landscape that has various forbs, grasses and shrubs has a greater potential of being desirable habitat for multiple animal species. A monoculture may provide habitat to only one or a few species of wildlife or livestock, and for only a portion of the year. From a landscape-scale perspective, the presence of a diversity of communities or vegetation types provides various aspects of habitat that are necessary for animal survival. Riparian systems are essential for watering areas, but uplands are as equally critical during winter months when the snow may be too deep in the riparian areas. Dense sagebrush may provide good hiding or thermal cover, but may be lacking in food resources. Managing for a diverse landscape increases the probability of that landscape meeting the needs of wildlife and livestock populations through time.
Increasing the diversity of an area can also greatly impact the utility of that system. If a system has both warm and cool season grasses, the pasture can be used in various ways. As we all know, with appropriate temperatures and precipitation, cool season grasses begin to green up and grow in the early spring. However, when the temperatures get too hot they begin to slow growth and their nutrient value often decreases. Warm season grasses, on the other hand, do not begin growing until later in the summer and continue to grow when the conditions are too warm for cool season species. As a manager, pastures with this type of diversity can be manipulated to increase use of both cool and warm season species, potentially enabling a longer or more varied opportunity for forage utilization in a grazing scenario.
Wyoming’s landscapes are rich in diversity and the various plants and animals that inhabit our great state is a strong indication of this. Take a quick look as you drive around Wyoming and you will continuously see diversity in various forms. Managing actively for diverse communities and landscapes will contribute to the long-term condition of our rangelands, livestock and wildlife that provide valuable resources to our state.